A controlled follow-up of cases involved in an epidemic of 'benign myalgic encephalomyelitis'

In 1955 an epidemic occurred among the staff of a London Teaching Hospital group. The nature of the epidemic remains uncertain. One view is that the illness was a viral encephalomyelitis (Medical Staff Report, 1957); an alternative is that it was a manifestation of anxiety spreading through a population consisting largely of young women (McEvedy and Beard, 1970). This paper reports the results from the follow-up study carried out in 1968–69 on the nuclear group affected by the epidemic and on a matched series of controls.